c/diesel-mechanics

Skeptical about ultrasonic cleaning, now I won't run injectors without it

I spent 15 years rebuilding injectors with just solvent and a wire brush, honestly thought those ultrasonic machines were overpriced hype for fancy shops. Last fall a customer from Omaha brought in a set of 6 injectors from a 6.7 Powerstroke with rough idle complaints, I did my usual cleaning and they still knocked on the bench. Buddy of mine let me borrow his 10 gallon ultrasonic tank for a weekend, so I tried it with the right heated solution at 140 degrees for 40 minutes. The carbon came off in sheets, tiny passages I couldn't even see before were actually clear, and the spray patterns looked perfect after I tested them. That set went back in and the truck ran smooth as new, customer even called me to say thanks which never happens. I bought my own 6 gallon unit for $700 a couple months ago and it has paid for itself twice already. Has anyone else been burned by cheap ultrasonic solutions, or is there a particular brand you swear by for diesel injectors?

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parker_bell•1d ago

The shop radio filter trick that saved my ears

Heard a younger guy in a shop in Tulsa raving about those earmuff style Bluetooth muffs with a built in mic. Figured he was just spoiled, but I tried a pair while running a dyno pull last Tuesday and could actually hear the knock sensor tone over the noise. Anyone else running active noise cancelling muffs, or is it just another gadget that gets lost by Friday?

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webb.val•2d ago

One Friday that nearly made me quit, then a buddy saved it

Last month I had a Friday where everything stacked against me. Started with a 2019 Cummins that kept losing oil pressure on a test drive, then the cab mount bolts on the next truck were rusted so bad I snapped two extractors. By noon my hands were cut up and I still had a PTO pump swap waiting. My friend Mike swung by and just watched for a minute, then pointed out the oil pressure sender wire was pinched under the harness bracket. Forty bucks in parts later the truck was fine. That same afternoon he helped me torch the cab mounts loose and we had the PTO done by 4. Anyone else have days where one guy's eyes save you hours of guessing?

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richard_hall•4d ago

My buddy swore by ATF in the fuel tank, I called him nuts

Last month my 2003 F-550 with the 7.3 started stumbling bad on the highway outside Tulsa. Injector noise got loud too. My buddy Don, who's been turning wrenches since the 80s, tells me to dump a quart of ATF in the tank with a full fill-up. I thought he was messing with me, but he said it cleans injectors better than any additive. So I humored him. Truck ran like garbage for the first 20 miles, smoke everywhere. Then it cleared up and pulled harder than it has in two years. Noise settled down too. Changed the fuel filter after that tank and it was black with crap. Don't know the science, but it worked. Anyone else run this trick, or did I just get lucky?

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the_kelly•5d ago

Chose a $200 scan tool over a $1200 one, regret it after a month

Picked up an Autel AP200 for my shop truck and passed on a used Verus. After 30 days, the AP200 just cant handle the forced regen on a 2019 Freightliner. I spent 4 hours at a customers yard in Phoenix trying to clear a code and it wouldnt do it. Had to borrow my neighbor's tool anyway. Should I just bite the bullet and buy the Verus now, or is there a mid range option that does forced regen without the dealer price tag?

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johns18•6d ago

TIL the hard way that a glow plug thread chaser is not a tap

Was doing a 7.3 Powerstroke in my shop near Fort Worth. Threads on cyl 5 looked a little rough so I grabbed what I thought was a chaser. Turned out it was a tap. Yeah. It cut new threads. Took me 4 hours and a helicoil kit to fix my own mess. Customer just watched me the whole time. He said "you gonna charge me extra for that?" Has anyone else grabbed the wrong tool out of habit and made a simple job way worse?

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johnfoster•13d ago

Conversation with a fleet manager about idle time made me check my own habits

Was doing a PM on a 2018 Freightliner last week and the fleet manager, Dave, started talking about how he cuts idle time by 15 minutes per truck per day. At first I thought he was just pinching pennies on fuel. But he showed me the data on regen cycles and DPF cleaning intervals. Idle time messes with soot load more than I ever figured. Now I pay attention to how long I let trucks sit and run before I shut them down or hook up a block heater. Has anyone else seen actual maintenance costs drop after clients cracked down on idle hours?

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rowank69•14d ago

Drove through Ohio and spotted the worst fuel filter setup I've seen in ages

Stopped at a truck stop outside Lima last Tuesday to help a buddy with his Freightliner. He had a secondary fuel filter mounted upside down with a homemade bracket, and the lines were routed right over the exhaust manifold. I pointed it out and he said it'd been like that for two years since he bought it used. Air in the system was causing hard starts every morning, and he blamed the lift pump. Has anyone else run into dangerously rigged filter mounts on older rigs, or is this just a Midwest thing I keep finding?

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sanchez.mia•16d ago

Hit 10,000 hours on my old 7.3 work truck, never thought it would make it

The odometer clicked over to 10,000 hours last Tuesday on my 2002 F-350. I've had this thing since 2011 and it's been a shop truck, tow rig, and daily beater all in one. Stock motor, never opened it up, just oil changes every 250 hours and a couple of injectors around 7,500. I was standing there with a coffee watching the numbers flip and honestly got a little choked up. That engine owes me nothing. How many hours are you guys seeing on your work trucks before something major gives out? I'm wondering if I'm on borrowed time or if this is normal.

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seth_green85•16d ago

Old timer at the parts counter saved me on a stuck injector

Guy behind the counter at Cummins in Tulsa told me to soak a seized injector in ATF overnight instead of torching it. I thought he was full of it, but after 6 hours of fighting with a slide hammer, I tried his way. Came back next morning, it broke loose on the first pull. Anyone else got a weird trick from a parts guy that actually worked?

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spencer_johnson22•16d ago

Switched to 5W-40 synthetic in my fleet, mileage went up 2 mpg

I got tired of fighting cold start knock on my 6.7s so I broke down and tried the fancy oil for a few months. After 3 oil changes across 4 trucks in Phoenix, the average fuel economy went from 15.8 to 17.9 mpg, plus the oil analysis came back with way less wear metals. Anyone else run full synthetic year round or is that just throwing money at the problem?

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the_henry•16d ago

Finally admitting I was wrong about ultrasonic parts cleaners

After fighting a clogged injector in a Freightliner for 3 days, I borrowed a buddy's $400 ultrasonic tank and it broke that carbon loose in 20 minutes, so now I'm wondering if that $1500 one at the supply house is actually worth it for a small shop like mine?

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the_ryan•17d ago

Oil sample came back clean after 4 years of worrying

Finally sent a sample from my C15 to Blackstone last month after putting it off since 2020. Numbers were all in range, even the wear metals. Have any of you gotten results back that changed how you run your maintenance schedule?

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jesse_barnes37•19d ago

An old fleet foreman's torque wrench lesson from 2007 still sticks with me

Back when I was green at a shop outside Tulsa, this guy named Earl showed me how he checked torque on head bolts. He didn't use the clicker, he used an old beam wrench and told me to feel the bolt stretch instead of listening for the click. At first I figured he was just stuck in his ways, but after a blown head gasket on a 5.9 I never forgot it. He said, 'The click is for the guy who doesn't trust his hands.' I still use a beam wrench on critical stuff, and it's cut down my comebacks a ton. Anyone else have an old-timer teach them something that never made it into any manual?

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james672•23d ago

Took a coolant sample and got a green smoothie instead

Last week I pulled a sample from a Freightliner Cascadia and the stuff came out thick and lumpy, kind of like a melted milkshake. The driver swore he'd been topping it off with plain water, but the oil analysis later showed a blown head gasket and about 3 quarts of engine oil mixed in. Cost the guy a new gasket set plus a full flush, around $1,800 all said. Has anyone else seen coolant turn into that weird pudding consistency before the engine even started knocking?

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valwest•25d ago

Hit 500 tool rebuilds in my shop, kept count since 2019

Slow Tuesday, so I added up my rebuild log. 500 injectors, turbos, and fuel pumps exactly. Started counting because I wanted to prove a point to my old shop foreman who said I'd never stick with bench work. Number 500 was a 6.7 Powerstroke injector out of a ranch truck near Abilene. Took me 45 minutes from pull to bench test. Five years ago that same job ate my whole afternoon. Repetition really does speed you up. Not saying I'm the fastest guy out there, just surprised I actually kept the count going this long. Anyone else track their rebuild numbers or done work. Or am I just weird with a spreadsheet?

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troy996•26d ago

Lost a weekend to a counterfeit oil pressure sensor off eBay

Grabbed a cheap sensor for my 7.3 because the dealer wanted $140, paid $25 shipped. It read 80 psi at idle and lit the dummy light on the highway, chased that phantom for 2 days before a buddy in Columbus told me to test the resistance. Has anyone else had luck with the cheaper sensors or do you all stick with OEM for this one?

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william917•27d ago

An old shop foreman's torque comment made me recheck everything

Back in 2018 I was working at a fleet shop outside Tulsa and this foreman, Larry, watched me torque down a set of head bolts on a 3126. He just said 'you trust the click, you trust yourself, but you never trust the first pass.' I thought he was being a cranky old guy but I started checking my torque wrench against a beam type and found it was reading 15 ft-lbs low. That one comment pushed me to calibrate every wrench I own every 6 months now, and I check the fastener threads for stretch before I even spin a nut on. It slowed me down at first, but I can't count the comebacks I avoided since then. Anyone else ever catch a bad torque wrench after trusting it for years?

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jesse84•27d ago

Bad week turned around after one injector swap

Last Tuesday was a disaster. Tore down a 6.7 Cummins, found the #5 injector was the issue after 3 hours of chasing a miss. Then my air hose split and soaked my gloves in diesel. Customer showed up early, hovered, kept asking if I was done. But once I swapped that injector and fired it up, it ran smooth as glass. That instant fix made the whole week better. Anyone else have a job that went sideways but ended perfectly?

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ivan_hayes29•27d ago

Six years running the same route, the trucks feel different now

I do line haul between Albuquerque and Santa Fe, about 130 miles a night. Back in 2018 I could predict every rattle in my old freightliner, now I'm running a 2023 Cascadia and it's almost too quiet. The real change I noticed is the emissions stuff, you go from a truck that needs a regen every few hundred miles to one that manages it on its own, but you also chase more sensor faults. Last month I popped a code for a clogged doser and it cost me two nights of downtime that I never would have had with the older mechanical pumps. The shop I use in Bernalillo said they see way more DEF system issues than injector or base engine problems now. The drivers I talk to say the same thing, the trucks start better in the cold but they don't trust them as far down the road. What's everyone else seeing with the newer engines, are you getting more work or less? Has anyone else dealt with the urea buildup on the newer Detroit units?

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felixward•28d ago

The injector guy in Abilene was right and I owe him an apology

I spent 3 days rebuilding a 6.0 with a used injector set my buddy swore by. He kept telling me to bench test each one before install, said it saves the headache later. I skipped it thinking they were fine and got a dead miss at idle plus a fuel knock. Pulled the rail again, found number 4 stuck open and trashed a fresh cup. Has anyone else learned the hard way that bench testing is non-negotiable, or am I the only stubborn one here?

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miles_grant35•1mo ago

Thought those $100 injector testers were a gimmick

Bought a cheap pop tester off eBay just to humor an old mechanic buddy. Found out three of my injectors were sticking at 1800 psi instead of 2600, cost me a blown head gasket later. Anyone else regret skipping proper diagnostics on a build?

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caseyw12•1mo ago

Had a TERRIBLE day at a job site in Atlanta last Friday

I was working on a 2015 Freightliner Cascadia and the EGR cooler decided to dump coolant into the intake mid-test. It took me 6 hours to tear it down and find the crack, all while the customer stood there watching. Turns out the cooler was aftermarket junk that had only 40k miles on it. That day sold me on always using OEM parts for emissions stuff, no exceptions. Anyone else had an aftermarket part fail way too early like that?

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finley939•1mo ago

Hot take: Stop yanking on wiring harnesses like they're tow straps

I was helping a kid in Portland swap an injector on a 6.0 last Saturday and he just grabbed the harness and pulled. He snapped two pins clean off and acted surprised. Is it really that hard to unclip the connector before you start pulling on it?

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felix_bailey45•1mo ago

A retired diesel mechanic in Billings showed me a valve adjustment trick I'd never seen before

I was helping him rebuild an old Cummins 5.9 and he pulled out a thin feeler gauge that was bent at a 45 degree angle. He said it lets you get into tight spots without taking the whole valve cover off again. What weird tool modifications have you guys picked up from old timers?

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